The survey by the University of Massachusetts at Amherst finds Warren leading Brown 43 percent to 39 percent -- just within the poll's 4.4 percent margin of error.
"These numbers could mean trouble for Scott Brown," said UMass political scientist Brian Schaffner. "The race is a dead heat and his support is well under 50 percent, which usually means difficulty for an incumbent, especially this far out from Election Day."
One sign of hope for Brown is that he leads Warren among independents by 18 points. But Schaffner noted that was not enough for the last GOP governor challenger to overcome the Bay State's overwhelming Democratic voter registration.
"Republicans must dominate the independent vote to win," Schaffner said. "Brown’s 18-point edge among Independents is impressive and similar to what Republican gubernatorial candidate Charlie Baker enjoyed in 2010, but that edge was not large enough to push Baker to victory."
Warren leads heavily among women and among people earning under $100,000, which the pollsters say is evidence that Warren's appeal to the working and middle class is resonating.
Read the entire survey here.